We calculate the correlation function of 13 904 galaxy clusters of z \leq 0.4 selected from the cluster catalog of Wen , Han & Liu .
The correlation function can be fitted with a power-law model \xi ( r ) = \left ( r / R _ { 0 } \right ) ^ { - \gamma } on the scales of 10 ~ { } h ^ { -1 } { Mpc } \leq r \leq 50 ~ { } h ^ { -1 } { Mpc } , with a larger correlation length of R _ { 0 } = 18.84 \pm 0.27 ~ { } h ^ { -1 } { Mpc } for clusters with a richness of R \geq 15 and a smaller length of R _ { 0 } = 16.15 \pm 0.13 ~ { } h ^ { -1 } { Mpc } for clusters with a richness of R \geq 5 .
The power law index of \gamma = 2.1 is found to be almost the same for all cluster subsamples .
A pronounced baryon acoustic oscillations ( BAO ) peak is detected at r \sim 110 ~ { } h ^ { -1 } { Mpc } with a significance of \sim 1.9 \sigma .
By analyzing the correlation function in the range of 20 ~ { } h ^ { -1 } { Mpc } \leq r \leq 200 ~ { } h ^ { -1 } { Mpc } , we find the constraints on distance parameters are D _ { v } ( 0.276 ) = 1077 \pm 55 ( 1 \sigma ) { ~ { } Mpc } and h = 0.73 \pm 0.039 ( 1 \sigma ) , which are consistent with the WMAP 7-year cosmology .
However , the BAO signal from the cluster sample is stronger than expected and leads to a rather low matter density \Omega _ { m } h ^ { 2 } = 0.093 \pm 0.0077 ( 1 \sigma ) , which deviates from the WMAP 7-year result by more than 3 \sigma .
The correlation function of the GMBCG cluster sample is also calculated and our detection of the BAO feature is confirmed .